Fluorination was confirmed to be the most effective route to introduce localized spins in graphene. However, adatoms clustering in perfect graphene lead to a low efficiency. In this study, we report experimental evidence of the generation of localized spin magnetic moments on defective graphene (reduced graphene oxide) through fluorination. More interstingly, the result shows that defects help increase the efficiency of the fluorination with regard to the density of magnetic moments created. Fluorinated reduced graphene oxide can have a high magnetic moment of 3.187 × 10<sup>–3</sup> μ<sub>B</sub> per carbon atom and a high efficiency of 8.68 × 10<sup>–3</sup> μ<sub>B</sub> per F atom. It may be attributed to the many vacancies, which hinder the clustering of F atoms, and introduce many magnetic edge adatoms.